Abstract: In an A/D conversion control apparatus for use in an electronic controller such as an engine ECU of a vehicle, each of successive sets of A/D converted values of an analog signal (each set comprising 3 or more values) is processed to obtain a median value of the set, and the median values are subjected to digital smoothing processing to obtain successive final result values, with effects of noise contained in the analog signal being effectively excluded. The final result values are suitable as control data, supplied to a control device such as a microcomputer of an ECU.

Abstract: An apparatus aims at detecting an angle of a rotating shaft as a train of bits. A first signal including a train of pulses corresponding to angle intervals of a rotation of the rotating shaft is inputted to the apparatus, and a second signal including a train of clock pulses whose clock cycle is a positive integer submultiple of a pulse cycle of the first signal is inputted to the apparatus. In the apparatus, a first counter is indicative of a higher-order of the train of bits, and counts up or down in synchronization with the pulse cycle of the first signal. A second counter is indicative of a lower-order of the train of bits, and counts either up or down in synchronization with the clock cycle of the second signal. The second counter is cleared in synchronization with the pulse cycle of the first signal.

Abstract: A knocking detecting device executes A/D conversion of a knock sensor signal every constant time ts and executes filter processing of the converted digital signal. The knocking detecting device determines whether the knocking arises or not according to the filter processed data. The device measures a TDC signal falling period T every 120° CA. The period indicating of 5° CA is divided by a constant period ts to obtain a value which is rounded off to derive an integer N. At a timing in which the crankshaft rotates to 10° CA from the TDC signal falling, the filter processed data which are derived every A/D timing ts are integrated every N pieces of data. When the number of integrated value reaches 12, knocking determining process is executed based on the 12 integrated values.

Abstract: In an electronic control unit for a vehicle, control data is stored in a volatile memory until a predetermined time passes after an ignition switch is turned off. This makes it possible to greatly reduce the frequency at which data is written into a nonvolatile memory. When the predetermined time has passed after the ignition switch is turned off, the control data stored in the volatile memory is written into the nonvolatile memory. Thereafter, the power supply from a power supply circuit to the volatile memory is stopped. Consequently, it is possible to store the control data reliably in either the volatile memory or the nonvolatile memory. It is also possible to reduce the dark current in the volatile memory.

Abstract: An apparatus is provided for detecting an occurrence of knocking of an engine from a signal sensed by a knocking sensor for the engine. The apparatus comprises plural filters extracting, from the signal, plural signal components whose frequency bands mutually differ and a unit determining whether or not there is the occurrence of knocking, based on results outputted from the plural filters. The plural filters include first and second types of filters. The first type of filter has a pass band set to a specific frequency band including a specific frequency of the signal. This specific frequency indicates the occurrence of knocking. The second type of filter has a pass band set to another specific frequency band. An inclination of a filtering characteristic of the second type of filter at a cut-off frequency thereof is steeper than that the first type of filter.

Abstract: A knocking detecting device executes A/D conversion of a knock sensor signal every constant time ts and executes filter processing of the converted digital signal. The knocking detecting device determines whether the knocking arises or not according to the filter processed data. The device measures a TDC signal falling period T every 120° CA. The period indicating of 5° CA is divided by a constant period ts to obtain a value which is rounded off to derive an integer N. At a timing in which the crankshaft rotates to 10° CA from the TDC signal falling, the filter processed data which are derived every A/D timing ts are integrated every N pieces of data. When the number of integrated value reaches 12, knocking determining process is executed based on the 12 integrated values.

Abstract: An A/D conversion apparatus includes four A/D conversion units, each comprising ring delay lines, pulse selectors for detecting the positions reached by pulse signals in the ring delay lines, encoders for converting the reached positions that are detected into ma-bit digital values, mb-bit counters for counting the number of times the pulse signals have circulated through the ring delay lines, and latch circuits for latching the results counted by the counters. A control circuit sends digital values obtained from the A/D conversion units to a signal processing circuit which adds up together the digital values to calculate a digital value having the number of bits larger than that of the initial digital value.

Abstract: An engine control apparatus receives a rotation signal composed of a train of pulses at every interval of a predetermined angle and having a reference position intermediate of the pulse train. A microcomputer in the apparatus executes a detection of the reference position by an interrupt at every effective edge of the rotation signal. Moreover, the microcomputer detects the crankshaft angle position on the basis of the detection result at the beginning of the start of the engine, and on the basis of the reference position signal after the engine start when it is determined that a signal processing circuit is normally operating, by making the reference position signal from the signal processing circuit effective.

Abstract: A signal-processing apparatus has a digital filter for processing input data from a knock-sensor. The digital filter is designed as an FIR filter characterized by filter coefficients that are equal to values of mince points 0 to 16 obtained based on a reference waveform. The reference waveform is created by concatenating half waves of a first sinusoidal waveform with half waves of a second sinusoidal waveform with peak values equal to half the peak value of the first sinusoidal waveform. The values of mince points 4, 8 and 12 are 0. Each value of mince points 1, 3, 13 and 15 is equal to corresponding value of mince points 5, 7, 9 and 11. The digital filter effectively reduces a filter-processing load.

Abstract: A control system and method for controlling operation of a group of linear solenoids, which in turn control operation of an electrical load such as a solenoid or actuator, that exhibits increased responsiveness to a change in the target linear solenoid load current. A microcomputer cyclically generates and outputs pulse-width-modulated drive signals based on acquired drive data to establish clock periods. A switch connected between the microcomputer and the target load switchably connects the target load to a power source based on the drive data to selectively drive the target load. A feedback loop between the target load and the microcomputer provides actual target load drive data to the microcomputer, and the microcomputer adjusts the drive signals at a rate of not more than two times per cycle based on the actual drive data to converge the actual drive data to a calculated target load drive value.

Abstract: An apparatus for determining combustion condition of engine detects ion current flowing in a spark plug. The apparatus samples the ion current by carrying out A/D conversion at every constant time period. The apparatus stores a maximum value of A/D converted values as a peak hold value. The apparatus further detects and stores that the ion current traverses a reference voltage during the A/D conversion time period. The apparatus clears the peak hold value, if the ion current traverses the reference voltage. The apparatus determines the combustion condition based on the peak hold value which has not been cleared continuously over a predetermined number of times of the A/D conversion. It is possible to reduce influence of noise.

Abstract: A control system and method for controlling operation of a group of linear solenoids, which in turn control operation of an electrical load such as a solenoid or actuator, that exhibits increased responsiveness to a change in the target linear solenoid load current. A microcomputer cyclically generates and outputs pulse-width-modulated drive signals based on acquired drive data to establish clock periods. A switch connected between the microcomputer and the target load switchably connects the target load to a power source based on the drive data to selectively drive the target load. A feedback loop between the target load and the microcomputer provides actual target load drive data to the microcomputer, and the microcomputer adjusts the drive signals at a rate of not more than two times per cycle based on the actual drive data to converge the actual drive data to a calculated target load drive value.

Abstract: A signal-processing apparatus has a digital filter for processing input data from a knock-sensor. The digital filter is designed as an FIR filter characterized by filter coefficients that are equal to values of mince points 0 to 16 obtained based on a reference waveform. The reference waveform is created by concatenating half waves of a first sinusoidal waveform with half waves of a second sinusoidal waveform with peak values equal to half the peak value of the first sinusoidal waveform. The values of mince points 4, 8 and 12 are 0. Each value of mince points 1, 3, 13 and 15 is equal to corresponding value of mince points 5, 7, 9 and 11. The digital filter effectively reduces a filter-processing load.

Abstract: An engine control apparatus receives a rotation signal composed of a train of pulses at every interval of a predetermined angle and having a reference position intermediate of the pulse train. A microcomputer in the apparatus executes a detection of the reference position by an interrupt at every effective edge of the rotation signal. Moreover, the microcomputer detects the crankshaft angle position on the basis of the detection result at the beginning of the start of the engine, and on the basis of the reference position signal after the engine start when it is determined that a signal processing circuit is normally operating, by making the reference position signal from the signal processing circuit effective.

Abstract: An A/D conversion apparatus includes four A/D conversion units, each comprising ring delay lines, pulse selectors for detecting the positions reached by pulse signals in the ring delay lines, encoders for converting the reached positions that are detected into ma-bit digital values, mb-bit counters for counting the number of times the pulse signals have circulated through the ring delay lines, and latch circuits for latching the results counted by the counters. A control circuit sends digital values obtained from the A/D conversion units to a signal processing circuit which adds up together the digital values to calculate a digital value having the number of bits larger than that of the initial digital value.

Abstract: An apparatus for determining combustion condition of engine detects ion current flowing in a spark plug. The apparatus samples the ion current by carrying out A/D conversion at every constant time period. The apparatus stores a maximum value of A/D converted values as a peak hold value. The apparatus further detects and stores that the ion current traverses a reference voltage during the A/D conversion time period. The apparatus clears the peak hold value, if the ion current traverses the reference voltage. The apparatus determines the combustion condition based on the peak hold value which has not been cleared continuously over a predetermined number of times of the A/D conversion. It is possible to reduce influence of noise.

Abstract: In an in-vehicle electronic control apparatus (ECU), when a microcomputer stops operation, a timer IC starts the count-up operation. When the count value reaches a preset value, a signal from the timer IC becomes high and a power supply voltage is outputted from a power supply IC to activate the microcomputer. The microcomputer reads the count value from the timer IC when it starts the operation. If such a count value has exceeded the specified value, the microcomputer determines occurrence of a failure. Therefore, if the timer IC cannot activate the power supply IC, the microcomputer can detect a failure upon activation with turning on of an ignition switch.

Abstract: A key-verifying apparatus for quickly determining whether a key is legitimate, even when a legitimate key is determined not to be legitimate in at least a first iteration of key-verifying processing due to a communication fault or the like. An immobilizer ECU sends query data to a key transponder, receives response data from the transponder, generates auto-response data from the query data and key-discriminating data, and repeats key-verifying processing through determination as to whether the key is a legitimate until the key is determined to be legitimate or until a predetermined number of iterations are completed.

Abstract: A serial communication system, which can improve a communication speed even when it takes long time to perform a process in accordance with a command. A serial communication apparatus includes a first and a second microcomputer, each of which has a relationship of a master/a slave. Each of the first and the second microcomputer has a CPU, a ROM, a RAM, a communication control portion, a serial communication block and so on. A serial communication clock (SCLK) is continuously sent from the first microcomputer to the second microcomputer. The serial communication block of each of the microcomputers has a pair of exchangeable shift registers. Each of the communication control portions reads a signal (SRXD) sent from the opposite side microcomputer by 16 clocks, and performs processes based on a process command in the read signal (SRXD) during the next 16 clocks.

Abstract: The resistance of an air-fuel-ratio sensor element is determined from current detected before changing an applied voltage to the sensor and current detected when a predetermined period elapses after changing the applied voltage to the sensor. A resistence detector includes operational amplifiers, resistors and transistors. The applied voltage is changed by switching the transistors to more accurately detect a resistance value.